3H-glucosamine electron microscope autoradiography after isolated labeling of the enamel organ or the dental papilla followed by reassociated toothgerm culture.

Electron microscope autoradiography was performed after isolated labeling with 3H-glucosamine of the enamel organ or the dental papilla of Swiss mice followed by reassociated toothgerm culture for 9.30 h and 19 h. After these two time intervals in case of an enamel organ labeling, numerous silver grains were observed in the intercellular spaces of the stellate reticulum indicating a concentrating and storing role of the latter. After dental papilla labeling, an almost complete absence of radioactivity was noted at 19 h. suggesting that 3H-glucosamine is not stored by the dental papilla. A clear labeling of the basement membrane area and of the adjacent aperiodic filamentous material found on the pulpal side was only observed after enamel organ labeling with 3H-glucosamine, suggesting an epithelial origin of the glycosaminoglycans found in these structures.